package exp5;



import java.net.*;

import java.io.*;

import java.security.*;

import java.security.spec.*;

import javax.crypto.*;

import javax.crypto.spec.*;

import javax.crypto.interfaces.*;

import java.security.interfaces.*;

import java.math.*;



public class Server {

    public static void main(String srgs[]) throws Exception {

        ServerSocket sc = null;

        Socket socket = null;

        try {

            sc = new ServerSocket(2530);// 创建服务器套接字

            System.out.println("端口号:" + sc.getLocalPort());

            System.out.println("服务器成功启动");

            socket = sc.accept(); // 等待客户端连接

            System.out.println("成功建立连接");

            // 获得网络输入流对象的引用

            BufferedReader in = new BufferedReader(new InputStreamReader(

                    socket.getInputStream()));

            // //获得网络输出流对象的引用

            PrintWriter out = new PrintWriter(new BufferedWriter(

                    new OutputStreamWriter(socket.getOutputStream())), true);



            String aline2 = in.readLine();

            BigInteger c = new BigInteger(aline2);

            FileInputStream f = new FileInputStream("Skey_RSA_priv.dat");

            ObjectInputStream b = new ObjectInputStream(f);

            RSAPrivateKey prk = (RSAPrivateKey) b.readObject();

            BigInteger d = prk.getPrivateExponent();

            BigInteger n = prk.getModulus();

            BigInteger m = c.modPow(d, n);

            byte[] keykb = m.toByteArray();

            String aline = in.readLine();// 读取客户端传送来的数据

            byte[] ctext = parseHexStr2Byte(aline);

            Key k = new SecretKeySpec(keykb, "DESede");

            Cipher cp = Cipher.getInstance("DESede");

            cp.init(Cipher.DECRYPT_MODE, k);

            byte[] ptext = cp.doFinal(ctext);

            String p = new String(ptext, "UTF8");

            System.out.println("客户端接发送的信息为：" + p); // 通过网络输出流返回结果给客户端

            String aline3 = in.readLine();

            String x = p;

            MessageDigest m2 = MessageDigest.getInstance("MD5");

            m2.update(x.getBytes());

            byte a[] = m2.digest();

            String result = "";

            for (int i = 0; i < a.length; i++) {

                result += Integer.toHexString((0x000000ff & a[i]) | 0xffffff00)

                        .substring(6);

            }

            System.out.println(result);



            if (aline3.equals(result)) {

                System.out.println("信息核对无误");

            }



            out.println("信息核对无误");

            out.close();

            in.close();

            sc.close();

        } catch (Exception e) {

            System.out.println(e);

        }

    }



    public static String parseByte2HexStr(byte buf[]) {

        StringBuffer sb = new StringBuffer();

        for (int i = 0; i < buf.length; i++) {

            String hex = Integer.toHexString(buf[i] & 0xFF);

            if (hex.length() == 1) {

                hex = '0' + hex;

            }

            sb.append(hex.toUpperCase());

        }

        return sb.toString();

    }



    public static byte[] parseHexStr2Byte(String hexStr) {

        if (hexStr.length() < 1)

            return null;

        byte[] result = new byte[hexStr.length() / 2];

        for (int i = 0; i < hexStr.length() / 2; i++) {

            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);

            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),

                    16);

            result[i] = (byte) (high * 16 + low);

        }

        return result;

    }

}